West Brom boss Roberto Di Matteo was full of praise for his battling Baggies after they won at Arsenal for the first time in 27 years.
Three second-half goals from Peter Odemwingie, Gonzalo Jara and former Arsenal player Jerome Thomas put Albion in dreamland before Samir Nasri scored two late consolation goals for the home side.
It left Arsenal four points adrift of Barclays Premier League leaders Chelsea while West Brom moved into fifth place.
“I would say we deserved it, the way we played, the way we created chances, scored goals and played very well,” said Di Matteo.
“We pressed them very high, we pressed them all over the pitch. We managed not to let them play their usual way. And when we had the ball we passed it very well and created chances ourselves.
“I don’t want us just to be pretty, I want results at the end of the day.
“We got a hammering at Chelsea and it wasn’t a pretty week after that, but we’ve learned. We’ve cut out those mistakes and that gives us a chance to stay in a game and win things.
“We go into games believing we can win. It was the way we won, we were not lucky. We played some tremendous football and defended well too.
“I knew at 3-0 in front the game wasn’t over because with the players Arsenal have on the pitch they will create chances.”
Crestfallen Arsenal boss Arsene Wenger admitted his side had been poor and did not deserve anything out of the game.
“We were poor and we got a poor result,” said Wenger. “We were poor everywhere, at the back, up front and in the middle of the park.
“We had an off day and were not good enough to win the game. I believe the concentration that gives you the sharpness was not there today.
“We made it more difficult because we were not at our usual level, defensively or offensively. Anything was difficult for us today, to pass the ball, to win it back.
“Overall we got what we deserved, that is zero points. We didn’t deserve more.”
Wenger refused to criticise goalkeeper Manuel Almunia who gave away a first-half penalty and then saved it before gifting Albion their second goal by letting Jara’s shot slip through his fingers.
“Well, you can have question marks over many players today if you look at the performance, especially defensively,” added Wenger. “Many players made massive mistakes defensively.
“I do not want to talk about any one performance, we were collectively poor. You could single out many players. Overall it was a poor team performance and we have to analyse why and respond well.
“It’s unexplainable how flat the whole thing looked for the whole game, it’s a mystery for me.
“Today in our performance something was not right. It was unusual to see a team as flat was we were.”